Valve deactivator for internal combustion engines

ABSTRACT

An internal combustion engine control system in which intake and exhaust valve deactivators are controlled in response to both engine throttle position and output speed in order to affect split engine operation. Voltages responsive to both throttle position and engine output speed are compared to generate a variable signal that controls the valve deactivators. Each deactivator includes a rotatable first cylindrical member axially fixed on an elongated engine support and also includes a second cylindrical member defining an enclosed cavity with the first member while positioned on the support between the engine and the first member. A helical spring of each deactivator encircles the cylindrical members thereof and has a first end axially fixed relative to the support and a second end that biases a rocker arm bearing toward the engine. Ports of the support and the first cylindrical member define inlet and exhaust passages to the cavity with the first cylindrical member in first and second rotational positions so as to allow the supply and exhaustion of pumped engine oil to the cavity in order to position the second cylindrical member and the bearing axially along the support so as to control valve operation. The deactivators associated with the intake and exhaust valves of selected cylinders are sequenced so that the intake valve ceases to operate prior to the cessation of the exhaust valve operation upon deactivation, and the exhaust valve begins to operate prior to the intake valve operation upon subsequent activation of the valves.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an internal combustion engine control systemfor affecting split engine operation and to valve deactivators used withthe intake and exhaust valves of the engine to control its operation.

2. Description of the Prior Art

Internal combustion engines that operate in a split engine mode toachieve fuel economy have been previously developed but have yet toachieve wide commercial usage. Selected cylinders of the engine aredeactivated during split engine operation so that no fuel is fed to thembut rather is fed only to the other cylinders. Intake and exhaust valvedeactivators are utilized to provide this control of the cylinderoperation. A V-8 cylinder engine will normally have one or two of itscylinders on each bank rendered inoperative by valve deactivators duringthe split engine operation to provide four or six cylinder operation andwill have all eight of its cylinders functioning during full engineoperation. Likewise, a V-6 cylinder engine will have one or twocylinders on one or both of its sides operating during split engineoperation for two, three, or four cylinder operation and all sixcylinders will function during full engine operation.

The United States Patent of Brown U.S. Pat. No. 3,964,455 discloses asplit engine valve deactivator including a movable piston that supportsan intermediate portion of the rocker arm of the valve. The piston islocated toward the engine from the rocker arm and positioned in an innerposition with respect to the engine to locate a push rod end of therocker arm so that a push rod pivots the rocker arm about a bearingmoved by the piston such that a valve actuating end of the rocker armopens and closes the associated cylinder valve. Positioning of thepiston in an outer position with respect to the engine locates thebearing such that telescoping portions of the push rod reciprocate withrespect to each other while a lash spring maintains engagement thereofwith the push rod and of the rocker arm, the net result being that nopivoting of the rocker arm takes place and hence no valve opening orclosing results despite the push rod movement.

See also U.S. Pat. Nos. 2,745,391; 2,955,750; and 3,874,358.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an internal combustionengine control system for affecting split engine operation in responseto throttle position and engine output speed.

Another object of the invention is to provide an improved valvedeactivator for an internal combustion engine intake or exhaust valve soas to control valve operation while having a compactly packagedconstruction, and without requiring any extensive molding or machiningof the engine with which the valve is used.

In carrying out the above objects, the valve deactivators are associatedwith the intake and exhaust valves of certain cylinders to controloperation of the valves. A V-8 cylinder engine disclosed has the valvedeactivators associated with the front and rear cylinders on one side ofthe engine and the two center cylinders on the other side of the engine.During full engine operation, all eight cylinders are functioning withtheir valves opening and closing, while during split engine operationthe valves of the cylinders with the deactivators are renderedinoperative so as to achieve fuel economy. Operation of the valvedeactivators is controlled by first and second sensors that generatevariable signals. The first sensor generates a variable signalresponsive to engine throttle position while the second sensor generatesa variable signal responsive to engine output speed. A comparator of thesystem compares the signals of the first and second sensors andgenerates a variable output signal that controls an actuator foroperating the valve deactivators.

In the preferred embodiment of the control system disclosed, the firstsensor is a potentiometer that generates a voltage proportional toengine throttle position while the second sensor is a dc tachometer thatgenerates a voltage proportional to engine output speed. The comparatorcompares the two voltages to control the valve deactivation of certaincylinders independently of other cylinders and concomitantly therewithin response to the magnitude of the output signal of the comparator.When utilized with a V-8 cylinder engine, all eight cylinders operateunder heavy-load conditions, while six cylinders operate undermedium-load conditions, and only four cylinders operate under light-loadconditions. Of course, a six or four cylinder engine could also utilizethis system in a similar manner with the number of cylinders controlledby the deactivators appropriately selected.

The improved valve deactivator disclosed includes first and secondcylindrical members encircled by a helical biasing spring and mounted onthe outer end of an elongated support whose inner end is supported onthe engine. An intermediate portion of the support mounts a bearing fora valve rocker arm. One end of the spring is axially fixed with respectto the support and with respect to the first cylindrical member which isrotatable between first and second positions to control the deactivatoroperation. The other end of the spring biases the bearing toward theengine to provide lash take-up during deactivation of the valve. In thefirst position of the fist cylindrical member, ports thereof and of thesupport define an inlet passage that supplies pressurized fluid to acavity defined by the first and second cylindrical members. Thispressurized fluid moves the second cylindrical member and the bearingtoward the engine so that the rocker arm is positioned for normal valveoperation. In the second position of the first cylindrical member, portsof the support and the first cylindrical member define an exhaustpassage that exhausts the pressurized fluid in order to permit outwardmovement of the second cylindrical member so that the bearing positionsthe rocker arm for pivoting about its valve actuating end uponreciprocation of its push rod end with the helical spring providing thelash take-up. An axial hole in the elongated support feeds thepressurized fluid to the cavity through the inlet passage and includes acheck valve that prevents reverse fluid flow.

Pumped engine oil can be utilized as the pressurized fluid whichcontrols the deactivator operation in order to provide an economical andlow maintenance system. Other valve deactivators, such as the onedisclosed by the previously mentioned U.S. Pat. No. 3,964,455, require acontrol fluid of a higher pressure than is present with pumped engineoil. While a vehicle power steering pump generates a sufficient pressureto control this type of deactivator, a separate fluid system is thenrequired and leakage thereof can be a problem since the power steeringfluid cannot be mixed with the conventional engine oil that lubricatesthe valves. However, exhaustion of the engine oil from the cavity of thevalve deactivator to the adjacent area about the rocker arm presents noproblem since this area is normally lubricated with the engine oilwithin the conventional rocker arm covers secured to the engine.

A spring fitting of the rocker arm bearing has a flanged portion thatseats the inner end of the helical spring which encircles thecylindrical members. A larger diameter portion of the second cylindricalmember slidably receives the first cylindrical member to cooperatetherewith in defining the cavity while a smaller diameter portion of thesecond cylindrical member is slidable on an intermediate portion of theelongated support mounted by the engine.

Rotational movement of the first cylindrical member of each deactivatoris controlled by a linkage that interconnects the valve deactivatorsassociated with the intake and exhaust valves of each cylinder.Rotational movement of the first cylindrical members and theorientations of the ports thereof defining the inlet and exhaustpassages are such that deactivation of the intake valve occurs beforedeactivation of the associated exhaust valve. Subsequent activation ofthe exhaust valve takes place before the activation of the associatedintake valve as the linkage is moved by the actuator linkage in responseto the control signals sent by the system. A crank arm of eachdeactivator is rotatably fixed to the associated first cylindricalmember while a linkage arm thereof is rotatably supported with respectto the first cylindrical member and rotatably secured to the crank armthereof by an adjustable connection.

The objects, features, and advantages of the present invention arereadily apparent from the following detailed description of thepreferred embodiment taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side elevation view of a vehicle incorporating aninternal combustion engine control system for affecting split engineoperation in accordance with the present invention;

FIG. 1a is a top plan view of the engine taken long line 1a--1a of FIG.1;

FIG. 2 is a graph showing a variable voltage signal that is sensed by afirst sensor of the system proportional to the extent of the openedthrottle condition;

FIG. 3 is a graph of a second variable signal that is sensed by a secondsensor of the system proportional to engine output speed;

FIG. 4 is a graph showing the manner in which a comparator of the systemcompares the first and second sensed signals illustrated in FIGS. 2 and3 in order to control the valve deactivators that affect split engineoperation;

FIG. 5 is a sectional view taken along line 5--5 of FIG. 1 through theengine showing one valve deactivator;

FIG. 6 is an enlarged sectional view through the deactivator taken alongline 6--6 of FIG. 5;

FIG. 7 is a sectional view of the valve deactivator taken along line7--7 of FIG. 6;

FIGS. 8a, 8b, 8c, and 8d are sectional views through valve deactivatorstaken in the direction of line 8--8 in FIG. 6, FIG. 8a showing anexhaust valve deactivator in its valve activated condition, FIG. 8bshowing the exhaust valve deactivator in its valve deactivatedcondition, FIG. 8c showing an intake valve deactivator associated withthe exhaust valve deactivator in its valve activated condition, and FIG.8d showing the intake valve deactivator in its valve deactivatedcondition; and

FIG. 9 is a plan view of the valve deactivator taken along line 9--9 ofFIG. 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to FIG. 1, a phantom line indicated vehicle 10 includes aV-8 cylinder engine 12 having a control system collectively indicated by14 for affecting split engine operation in a manner according to thepresent invention. Engine 12 drives through a transmission 16 whoseoutput is connected to a drive shaft 18 with a rear end coupled to therear wheel differential 20. Of course, engine control system 14 is alsousable with a front wheel drive vehicle and the rear wheel driveembodiment disclosed is for illustrative purposes only.

With combined reference to FIGS. 1 and 1a, each of the engine cylinders20 includes an intake valve 22 and an exhaust valve 24 for feedingcombustible charges to these cylinders and for receiving burnt chargestherefrom in a conventional manner. The front and rear cylinders 20 onone side of the engine and the two middle cylinders on the other side ofthe engine include valve deactivators whose structure for affectingsplit engine operation will be subsequently described. An actuatorcollectively indicated by 25 for operating the valve deactivatorsincludes linkages 26 with link arms 28 connected to each of the valvedeactivators. Rear ends of the linkages extend into vacuum cylinders 30and are connected to pistons 32 which are sealingly slidable within thecylinders. Engine vacuum is fed through a Y-shaped conduit 34 whosebranches include respective control valves 36 operated by associatedsolenoids 38 through mechanical connections 40. When either solenoid 38is actuated to open its associated control valve 36, engine vacuum isfed into the right side of the associated cylinder 30 to move the piston32 to the right against the bias of a spring 42. This movement of thepiston moves the linkage 26 to the right and thereby causes the linkagearms 28 to pivot and operate the exhaust and intake valve deactivatorsof the cylinders 20 in a manner hereinafter described.

As can be seen in FIG. 1, the first sensor 44 of the control system 14is embodied as a potentiometer which has a mechanical linkage connection46 to the throttle valve 48 of carburetor 50. Opening movement of thethrottle valve 48 moves an arm 52 of the potentiometer sensor 44upwardly along a resistor 54. Battery 56 is connected by wires 58 and 60to the resistor 54 with the negative side of the battery and wire 60grounded at 61. As the throttle valve is opened and potentiometer arm 52moved upwardly, a variable voltage signal is generated and fed to a wire62 proportional to the opened condition of the throttle. This signal isgraphically illustrated by FIG. 2 wherein the voltage signal 64 is in astraight line relationship that has a value of six volts at one-halfopened throttle position and twelve volts when the throttle is fullyopened. A second sensor 66 of the control system 14 is embodied as a dctachometer that is grounded at 68 and mechanically connected at 70 tothe vehicle drive shaft 18 or any other suitable location such as thedistributor for sensing engine output speed. A wire 72 is fed a variablevoltage signal from the tachometer sensor 66 as shown by the graphicalrepresentation of FIG. 3. Voltage signal 74 increases in a straight linerelationship proportional to vehicle speed so as to reach twelve voltsat sixty miles per hour, which corresponds to an engine speed of about5000 revolutions per minute.

A grounded comparator 76 of the control system 14 is shown in FIG. 1connected to the wire 62 of the first sensor 44 and connected with thewire 72 of the second sensor 66. Conventional electrical circuitry ofthe comparator 76 compares the two voltage signals 64 and 74 shown inFIGS. 2 and 3 of the first and second sensors, respectively, andcontrols the two solenoids 38 in response to the voltage differencesensed between these signals. This voltage difference is variable inaccordance with the condition of engine operation and represents anoutput signal of the comparator. Each of the solenoids 38 is connectedby an associated wire 78 to the comparator and is grounded at 80 so thata control voltage supplied to the wire energizes the solenoid.

When the comparator 76 shown in FIG. 1 senses the throttle voltage 64shown in FIG. 2 as being one volt or more greater than the tachometervoltage 74 shown in FIG. 3, the vehicle engine operates with all eightcylinders. But, when the throttle voltage is greater than the tachometervoltage by less than one volt, one of the solenoids 38 is actuated sothat the valves of the two cylinders associated therewith aredeactivated to thereby provide six cylinder operation of the engine. Athrottle position voltage equal to or less than the tachometer voltagesensed by the comparator causes both of the solenoids to be energized sothat the four cylinders having valve deactivators are all renderedinoperative to provide four cylinder operation of the engine. It shouldbe understood that the solenoids may be identical and supplied differentenergization voltages by their respective wires 78 in order to providethis selective solenoid operation. On the other hand, the wires 78 mayprovide the same voltage from the comparator and the solenoids may havea different level of voltage requiring energization to deactivate theassociated cylinder valves.

FIG. 4 shows a driving sequence beginning with an idle condition at theorigin. As the accelerator pedal is depressed along a line A to atwo-thirds open position corresponding to eight volts, vehicle speedinitially increases relatively slowly. Due to the difference between thethrottle and speed voltages of greater than one volt, the control systemsolenoids will be deactuated and all eight cylinders will then beoperating. Speed subsequently increases along a line B as the throttleremains at a constant position with all eight cylinders continuing tooperate. When the speed increases sufficiently so that the differencebetween the throttle and speed voltages is less than one volt, thecomparator will actuate one of the solenoids 38 so that two cylindersare deactivated and six cylinder operation will then take place. Speedcontinues to increase during six cylinder operation until the throttleand speed voltages are equal at the steady state point of S.S., i.e.about 40 miles per hour. The other solenoid 38 is then energized by thecomparator 76 so that two more cylinders are deactivated and fourcylinder engine operation thus occurs. Subsequent depression of thethrottle to the fully opened condition such as for passing causesmovement along a line C as the vehicle speed lags and increases veryslowly if at all. One of the control system solenoids is very rapidlydeenergized and a brief period of six cylinder operation takes placebefore the other solenoid is also deenergized for eight cylinderoperation during the throttle depression. Speed picks up along a line Das the inertia is overcome as the eight cylinder engine operationcontinues. Releasing the throttle from the fully opened condition to thetwo-thirds opened condition then causes movement along a line E brieflyback through the six cylinder operation into the four cylinder operationprior to the vehicle decelerating along line F back to the steady statecondition at point S.S. A subsequent full release of the acceleratorpedal and throttle movement to its idle position causes an initialmovement along line G and then along H as speed decreases duringmovement back to the origin.

Referring to FIG. 5, a valve deactivator 80 of this invention is shownwith an exhaust valve 24 associated with one of the cylinders 20 tocontrol valve operation during reciprocal movement of the piston 82within the cylinder. The valve deactivator controlling the associatedintake valve has the same structure as the exhaust valve deactivatorshown as do the other deactivators except for differences which will besubsequently noted. Reciprocal movement of a solid push rod 84 alongarrow A actuated by an unshown cam shaft pivots a rocker arm 86 so as toreciprocate a valve stem 88 whose lower end carries the valve head 90that opens and closes the valve opening 92 to the cylinder. A bearing 94of the deactivator 80 pivotally supports an intermediate portion 96 ofthe rocker arm with its push rod and valve actuating ends 98 and 100,respectively, maintained in engagement with the upper ends of the pushrod 84 and the valve stem 88. Helical spring 102 has one end seatedagainst the engine head 104 and another end seated against a fitting 106on the valve stem. Rocker arm cover 108 is secured to the engine head bybolts 110 to enclose the exhaust valve 24 and its associated deactivator80 as well as the other valves and deactivators on the same side of theengine.

With reference to FIG. 6, first and second round cylindrical members 112and 114 of the valve deactivator 80 are sealingly slidable in an axialrelationship with respect to each other to define an enclosed cavity 116whose volume varies as the sliding takes place. An elongated support 118of the deactivator includes a threaded inner end 120 received by athreaded hole 121 of the engine head 104 so as to project outwardlythrough the bearing 94 as well as axially through the first and secondcylindrical members 112 and 114 along their direction of movementrelative to each other. An outer end 122 of support 118 rotatablysupports the first cylindrical member 112 for movement between first andsecond positions in a manner that is subsequently described while beingaxially fixed at the location shown. Pressurized fluid received with thecavity 116 locates the second cylindrical member 114 in the innerposition shown with respect to the engine so that the rocker arm bearing94 is located inwardly as shown in both FIGS. 5 and 6 by solid linerepresentation such that actuation of exhaust valve 24 shown in FIG. 5takes place. Exhaustion of the pressurized fluid within the cavity 116(FIG. 6) allows outward movement of the second cylindrical member 114under the impetus of the outward movement of push rod 84 (FIG. 5) suchthat the rocker arm pivots about its valve actuating end 100 withoutopening and closing the valve due to the valve spring 102. As thedeactivated valve remains closed with the rocker arm 86 pivoting aboutits end 100, a helical spring 124 that encircles the first and secondcylindrical members flexes so as to provide lash takeup. One end ofspring 124 is axially fixed with respect to the elongated support 118while the other end of the spring is seated by a spring fitting 126 thatengages the rocker arm bearing 94. Spring 124 has a bias which isrelatively light in comparison to the bias of the valve closure spring102 so that the valve remains closed with spring 124 flexing in thevalve deactivated condition.

The outer end of support 118 is shown in FIG. 6 as having an axial hole128 through which a tube 130 extends to supply pumped engine oil througha hose coupling 132 to the cavity 116. A check valve 134 with a valveelement 136 biased upwardly against the lower end of tube 130 by aspring 138 prevents reverse flow of the pumped engine oil from thecavity 116 upwardly back through the tube.

As seen in FIGS. 6 and 8a, diametrically opposed ports 140 in theelongated support 118 cooperate with ports 142 and 143 in the firstcylindrical member 112 with this member located in a first rotationalposition thereof in order to define an inlet passage through which thepumped engine oil is fed from the tube 130 into the cavity 116. As thispumped fluid is fed into the cavity 116, the second cylindrical member114 is positioned in its solid line indicated inward position in FIG. 6in order to position the rocker arm bearing 94 inwardly with respect tothe engine and maintain the rocker arm 86 in a position for actuatingthe associated engine valve. Rotational movement of the firstcylindrical member 112 to a second rotational position thereof shown byFIG. 8b aligns the ports 142 and 143 thereof with the lower ends ofdiametrically opposed vertically extending ports 144 in the elongatedsupport 118. Upper ends of ports 144 respectively communicate with upperexhaust ports 146 and 147 of the first cylindrical member so that all ofthese ports define an exhaust passage in the second rotational positionof the first cylindrical member 112. The inlet passage for pumped oil tothe cavity 116 is then closed so that the second cylindrical member 114can move upwardly to the phantom line position shown in FIG. 6 as engineoil is forced out of both ports 146 and 147 and splashed about thevalves under the valve cover 108 shown in FIG. 5. As the push rod 84reciprocates with the deactivator 80 in this exhausted condition, therocker arm 86 pivots about its valve actuating end 100 with its push rodend 98 moving upwardly and downwardly. The intermediate portion 96 ofthe rocker arm also moves upwardly and downwardly with the helicalspring 124 providing lash take-up. Frictional forces involved willmaintain the second cylindrical member 114 upwardly in the phantom lineindicated position of FIG. 6 in a generally stationary manner. Noactuation of the engine valves takes place under this exhaustedcondition of the cavity 116. On the other hand, engine oil pumped intothe cavity 116 positions the second cylindrical member 114 downwardly inits solid line indicated position of FIG. 6 so that the reciprocalmovement of the push rod 84 (FIG. 5) pivots the rocker arm 86 to openand close the exhaust valve 124.

As seen best in FIG. 7, the linkage 26 which connects the deactivators80 on each side of the engine is connected to the outer end of linkagearm 28 by a schematically indicated ball and socket connection 148. Aninner end of linkage arm 128 is formed with a downwardly opening supportportion 150 of a round shape that receives a round nut 152 threaded ontoan upwardly projecting threaded portion 154 of the support outer end122. An omega-shaped retainer 156 is received by a groove 158 in thethreaded portion 154 to prevent unthreading and outward movement of thelinkage arm 28. Engagement of the upper surface 160 of cylindricalmember 112 with the lower side of nut 152 limits outward axial movementof the first cylindrical member while permitting rotation thereof aboutthe support 118. A crank arm 162 is located below the linkage arm 28 andhas a flanged periphery 164 that seats the upper end of helical spring124. A central opening of the crank arm 162 includes splines 166 thatare intermeshed with splines 168 on the upper end of cylindrical member112 so that the crank arm 162 is rotatably fixed to this cylindricalmember. An adjustable connection 170 rotatably fixes the linkage arm 28and the crank arm 162 to each other. Screw 172 of the connection extendsdownwardly through an arcuate slot 174 (See also FIG. 9) in the linkagearm 28 into a threaded hole 176 in crank arm 162. Loosening of the screw172 allows the linkage arm 28 to be rotatably adjusted with respect tothe crank arm 162 and thus with respect to the cylindrical member 112.Tightening of screw 172 rotatably fixes the linkage arm 28 with respectto the crank arm 162 and hence with respect to the cylindrical member112.

The exhaust valve deactivator 80 shown in FIGS. 8a and 8b includes a pin178 that projects radially from support 118 within port 146 ofcylindrical member 112. Engagement of the pin 178 with the oppositesides of the port 146 limits the rotational movement of cylindricalmember 112 under the impetus of the linkage 26 between the first inletposition of FIG. 8a and the second exhaust position of FIG. 8b. It willbe noted that the pin 178 is located to one side of the centerline oflinkage 26 by an angle of approximately five degrees. Another valvedeactivator indicated by 80' in FIGS. 8c and 8d is used with the intakevalve that cooperates with the exhaust valve deactivator 80 shown inFIGS. 8a and 8b at the same piston cylinder. Deactivator 80' has thesame construction as the deactivator structure previously describedexcept for the orientation of its pin 178. As can be seen, this pin 178is located on the opposite side of the centerline of linkage 26 by anangle of about five degrees. The orientation of the exhaust valve andintake valve deactivator pins 178 sequences the deactivators 80 and 80'so that the intake valve operation begins after exhaust valve operationbegins upon activation of the valves and so that exhaust operationterminates after intake valve operation has already terminated upondeactivation. This sequencing prevents a combustible charge from beingignited when the operation of the cylinder is in a transition stage withits exhaust valve closed.

With reference to FIGS. 8a and 8c, cylindrical member 112 of the exhaustvalve deactivator 80 is located approximately ten degrees clockwise fromthe cylindrical member 112 of the intake valve deactivator 80'. As such,as the members 112 are rotated clockwise with each other by linkage 26from their valve deactivated positions respectively shown by FIGS. 8band 8d, the exhaust valve deactivator inlet ports 142 and 143 move intoalignment with the stationary ports 140 prior to the alignment of thesesame ports for the intake valve deactivator. As such, the exhaust valvebegins to operate before the intake valve. Similarly, as the cylindricalmembers 112 of the deactivators 80 and 80' rotate counterclockwise toprovide valve deactivation, the ports 144 of the intake valvedeactivator are aligned with the ports 142, 146 and 143, 147 beforethese same ports of the exhaust valve deactivators so that the intakevalve terminates operation before the exhaust valve. Thus, during thetransition between valve operation and deactivation and between valvedeactivation and operation, there are no times at which a burnt chargeignited within the cylinder cannot escape through the exhaust valve dueto prior deactivation or a lagging of its activation.

It should be noted that the spring fitting 126 shown in FIG. 6 has anupper end with an angular flange 180 seating the lower end of thehelical spring 124 which provides lash takeup during valve deactivation.A lower end 182 of spring fitting 126 also has an annular shape thatengages the rocker arm bearing 94 under the bias of the spring 124. Anintermediate portion 184 of the elongated support 118 has a closesliding fit with a smaller diameter portion 186 of the secondcylindrical member 114. A larger diameter portion 188 of cylindricalmember 114 slidably receives the first cylindrical member 112 in asealed relationship. With the cavity 116 of the deactivator exhausted,friction involved between the support intermediate portion 184 and thesmaller diameter portion 186 of cylindrical member 114 as well as thefriction between the larger diameter portion 188 of cylindrical member114 and the cylindrical member 112 maintains the cylindrical member 114in this upward position against the downward bias of gravity as theintermediate portion 96 of the rocker arm moves upward and downwardlyalong a sleeve bearing 190 that encircles the lower support end 120.

While the preferred embodiment of the internal combustion split enginecontrol system and valve deactivator thereof have herein been describedin detail, those skilled in the art will recognize various alternativedesigns and embodiments for practicing the present invention asdescribed by the following claims.

What is claimed is:
 1. An internal combustion engine cylinder valvedeactivator comprising: first and second cylindrical members sealinglyslidable in an axial relationship with each other to define a cavitytherebetween of a volume that varies upon relative axial sliding betweenthe members; an elongated support having an inner end mountable on anengine and an outer end extending axially through the cylindricalmembers to axially fix the first cylindrical member relative to theengine while permitting rotation thereof; said second cylindrical memberbeing located between the engine and the first cylindrical member formovement toward and away from the engine; a bearing movable toward theengine with the second cylindrical member; a rocker arm including anintermediate portion mounted by the bearing and having push rod andvalve actuating ends on opposite sides of the bearing; an inlet passagefor feeding pressurized fluid to the cavity in a first rotationalposition of the first cylindrical member to move the second cylindricalmember axially toward the engine so that the rocker arm is positioned bythe bearing to actuate an associated engine cylinder valve; an exhaustpassage for exhausting the pressurized fluid from the cavity in a secondrotational position of the first cylindrical member so that the secondcylindrical member is movable away from the engine block to deactivatethe valve operation; and a helical spring that encircles the first andsecond cylindrical members and includes a first end axially fixed withrespect to the support and also includes a second end seated by thebearing so as to bias the bearing and rocker arm toward the engine tothereby provide lash takeup of the bearing and rocker arm when thecavity is exhausted.
 2. A valve deactivator as in claim 1 wherein thebearing includes a spring fitting with a flanged portion that seats thesecond end of the spring, a crank arm rotatably fixed to the firstcylindrical member, a linkage arm rotatably supported with respect tothe first cylindrical member, and an adjustable connection thatrotatably fixes the linkage arm to the crank arm and thereby alsorotatably fixes the linkage arm to the first cylindrical member.
 3. Avalve deactivator as in claim 1 wherein the first cylindrical member andthe support include ports that define the inlet and exhaust passages,the support having an upper end including a hole for feeding pressurizedfluid to the cavity through the inlet passage, and a check valve thatprevents the pressurized fluid from flowing from the cavity back throughthe inlet passage and through the hole in the support.
 4. An internalcombustion engine cylinder valve deactivator comprising: first andsecond cylindrical members sealingly slidable in an axial relationshipwith each other to define a cavity therebetween of a volume that variesupon relative axial sliding between the members; an elongated supporthaving an inner end mountable on an engine and an outer end extendingaxially through the cylindrical members to axially fix the firstcylindrical member relative to the engine while permitting rotationthereof; said second cylindrical member having a larger outer end thatreceives the first cylindrical member and a smaller inner end thatreceives the support such that the second cylindrical member is locatedbetween the engine and the first cylindrical member for movement towardand away from the engine; a bearing movable toward the engine with thesecond cylindrical member; a rocker arm having an intermediate portionmounted by the bearing and having push rod and valve actuating ends onopposite sides of the bearing; ports in the support and firstcylindrical member defining an inlet passage for feeding pressurizedfluid to the cavity in a first rotational position of the firstcylindrical member so as to move the second cylindrical member axiallytoward the engine so that the rocker arm is positioned to actuate anassociated engine cylinder valve; ports in the support and the firstcylindrical member defining an exhaust passage for exhausting thepressurized fluid from the cavity in a second rotational position of thefirst cylindrical member so that the second cylindrical member ismovable away from the engine; a helical spring that encircles the firstand second cylindrical members and includes a first end axially fixedwith respect to the support and also includes a second end seated by thebearing so as to bias the bearing and rocker arm toward the engine andto thereby provide lash takeup of the bearing and rocker arm when thecavity is exhausted; a crank arm rotatably fixed to the firstcylindrical member; a linkage arm rotatably supported relative to thefirst cylindrical member; and an adjustable connection that rotatablyfixes the linkage arm to the crank arm and thereby also rotatably fixesthe linkage arm to the first cylindrical member.